In a general solar cell module, an output lead wire of a solar cell panel and a terminal plate in a terminal box are soldered or securely sandwiched using resin components to electrically connect the terminal box to the solar cell array having a plurality of solar cells arranged therein.
In general, a solar cell module has a plurality of sealed strings having solar cells connected in series, and output lead wires led from the strings into the terminal box. The terminal box includes a plurality of terminal plates and bypass diodes spanning a space between the respective terminal plates. Each of the terminal plates has one end connected to the output lead wire led from the string and the other end connected to a module coupling cable. The output lead wire is formed of a conductive material and has one end connected to an electrode of the string and the other end connected to the terminal plate of the terminal box. In some case, the inside of the terminal box is filled with a potting material that is an insulating material to keep the insulation property.
Connections between the output lead wires and the terminal plates are locations where the entire current generated by relevant solar cells flows. If the output lead wire and the terminal plate are separated from each other due to the poor adhesion at the connection therebetween, an electrical resistance is generated at the connection between the output lead wire and the terminal plate, and the terminal box may be damaged due to abnormal heat generation. The connection between the output lead wire and the terminal plate may be subjected to various stresses such as an internal stress for a long term. Accordingly, the electrical connection portion between the output lead wire and the terminal plate needs to closely adhere together at the electrical connection so as not to prevent the separation.
To improve the reliability of the electrical connection between the output lead wire and the terminal plate and prevent the occurrence of abnormal heat generation due to the separation at the connection, Patent Literature 1 discloses a method of bending the output lead wire led from the string, in a direction from an upper side of a hole of the terminal plate to a lower side of the hole, and subsequently soldering the output lead wire to the terminal plate to achieve the electrical connection therebetween.